Conductivity Meter – ConductiSense

The ConductiSense range of online conductivity meters from Pi utilize the very latest and best conductivity sensors available in the world today for measuring the online conductivity of any aqueous solution.

Online conductivity meters are common in today’s water treatment and process plants. ConductiSense is a stable, reliable, online conductivity meter for a reasonable cost.

The ConductiSense sensors and accessories are available with different controllers giving you the same great performance with different communication, display, and control options. With the ConductiSense range of Conductivity Monitors, you get everything that you need – and nothing that you don’t.

Principle of Operation of Graphite Sensor

Graphite probes

Our light industrial conductivity sensor utilizes Graphite technology. The durable epoxy body construction provides a rugged and dependable sensor for potable water and clean water. Mount them in-line, in a pipe “T” fitting, or submerse them into a tank. For many applications, the epoxy body conductivity sensors are the lowest cost, most reliable conductivity sensor to use, especially for process applications. Rugged epoxy bodies make the sensors virtually unbreakable. These are an excellent choice to use as standard online conductivity electrodes in the water and related industries.

Principle of Operation of the Toroidal Sensor

Toroidal probe

The toroidal inductive conductivity sensors features a wide measurement range and dependable toroidal technology over the range 0-2,000,000 μS/cm. Resistant to corrosion, coatings and fouling common to contacting conductivity sensors, this probe is designed for a trouble free and long service life. Noryl is the standard material of construction and has a wide solvent tolerance and temperature stability to 105°C. All models can be submersed by utilizing the 3/4” NPT threads on the sensor or installed in 2” NPT tees for in-line deployment. A temperature sensor is built into the conductivity sensor for automatic temperature compensation.

Key Benefits

Options

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FAQs

Resists coating, corrosion and fouling

Durable Noryl (plastic) construction

Easy installation

Low purchase cost

Custom tee for in-line mounting

Boiler Conductivity Sensor

Stainless Steel probe

A variety of stainless steel sensors are also available for high temperature applications. Please contact us for further information.

Conductivity is the measurement of the ionic species in a solution. It is defined as the conductance in a given volume. Conductance is the ability of the solution to conduct electric current.

How are conductivity and conductance related?

Conductance is the ability of a solution to conduct electric current, while conductivity is the conductance in a given volume (usually measured in μΩ/cm or μS/cm).

How does temperature affect conductivity readings?

Temperature has an effect on your conductivity measurement but all Pi Conductivity Sensors have a built-in temperature sensor and provide automatic temperature compensation.

Can conductivity be measured in aqueous solutions only?

No, all substances possess some conductive properties. Generally organic compounds (such as benzene, alcohols, and petroleum products) have very low conductivities, while metals have very high conductivities. Measuring the conductivity of highly flammable liquids is very risky.

What is a cell constant and why are there different ones?

The cell constant, K, is equal to the area (a) normal to the current flow in centimeters squared divided by the distance in centimeters between the electrodes (d). For solutions with low conductivities the electrodes can be placed closer together or made larger so that the cell constant is less than one. This has the effect of raising the conductance so as to produce a value more easily measured by the electronics. The opposite also applies, in high conductivity solutions, the electrodes are placed farther apart or made smaller. Different cell constants are used as range multipliers. The standard K value is 1 with a K value of 0.1 being used for low conductivity water and a K value of 10 for higher conductivity water.

How are conductivity and TDS related?

Dissolved solids in a solution (TDS) contribute to the conductivity of that solution. Most people are happy to use a standard multiplier to convert conductivity to TDS (typically 0.65). This multiplier works for a NaCI solutions. Different solutions will have different multipliers.

How do I calibrate my meter for TDS if my dissolved solids are not the same as those in the calibration solutions sold?

Making your own standard will yield the most accurate results. This is done by making a mixture of salts in relative proportions that simulate the solution to be tested, then dissolving the mixture into distilled water. This should be done according to the following formula: 1 mg salt mixture/liter of distilled water = 1 ppm TDS, or in other words, X ppm TDS = X mg of salts + one liter of distilled water.

Remember that “X mg of salts” is the number of milligrams of a mixture of salt whose proportions simulate your test solution. An appropriate value for “X” is determined by the following rule:
Choose a ppm value for a calibrated solution as close as possible to the expected ppm values of the test solutions. If the ppm content of the test solution is expected to vary a great deal, it is best to choose a ppm value for the calibrated solution in the upper 1/3 of the TDS conductivity range.

What is the difference between micromhos (µ℧/cm) and microsiemens (μS/cm)?

There is no difference. Micromhos (µ℧/cm) is more common in the U.S., while microsiemens (μS/cm) is more common in Europe.

How should I store my conductivity electrode?

Rinse it in tap water when you are finished using it. You can store your electrode either wet or dry. If it is stored dry you will need to recondition the electrode before use.

How do I condition or recondition a probe?

Place the probe in a standard solution or tap water and have power running to the probe. Let the probe soak for 30 minutes to 1 hour unless otherwise specified.

What is the difference between conductivity and salinity?

The probe is the same for conductivity and salinity, but in a salinity meter a correction factor is applied to the reading. The correction factor takes the conductivity reading and converts it to ppm of a specific salt. The salt varies from manufacturer to manufacturer of standardized solutions. Some use NaCl while others use CaCO3.

Are conductivity probes interchangeable with meters?

Usually the Pi electronics can accommodate other sensors. Please contact Pi for help.

How and when do I need to calibrate the probe?

Calibrate using a standard solution in the range of the samples you are testing. Place the probe in standard solution, condition, rinse the probe in second sample of standard solution, use a third sample of standard solution to calibrate, and then adjust on the analyzer until the specified value is displayed. Recalibrate when you change ranges, or if readings seem to be incorrect.

How do I choose my range for a conductivity sensor?

The two types of conductivity sensor supplied by Pi are ‘Toroidal’ and ‘Graphite’. The ‘Toroidal’ sensor covers the higher ranges from 0 µS/cm to 2,000,000 µS/cm or more often expressed as 0 mS/cm to 2000 mS/cm. The ‘Graphite’ sensor covers the range from 0-5000 µS/cm. Within that range we use different range constants (K- factor) to make the sensor more suitable for different applications. If you are measuring in the range 0-100 µS/cm then you will need a K- factor of 0.1. If you are measuring in the range 0-1000 µS/cm then a K-factor of 1.